$NRG is one of biggest losers #stocks today. read more:

NRG Energy, Inc. Common Stock (symbol: NRG) was one of the worst losers of
the trading day today (2015-12-04), losing -17.96%. The number of shares
that changed hands was 28,915,784, or about 4 times the average daily
volume in the stock.
The closing price was $9.0, amounting to a market cap of $2,830,000,000,
about -68.53% off the highest price in the last 12 months. The stock has
been trading at a range between $8.81 and $28.6.
NRG is in the Electric Utilities: Central industry, part of the Public
Utilities sector.